Exhaust gas separating tower and exhaust gas separating and recycling system

Abstract

The invention relates to an exhaust gas separating tower, comprising a washing section, a flash-distilling section above the washing section, and a liquid seal means between the flash flash-distilling section and the washing section. The washing section is configured for washing exhaust gas entering the tower with a cooling liquid to at least partially remove solid dust entrained in the exhaust gas, cool the exhaust gas, and condense at least a portion of moisture in the exhaust gas into liquid. The flash-distilling section is configured for flash-distilling the cooling liquid from the washing section to produce a cooled cooling liquid and a cooling liquid vapor. The liquid seal means is configured so that the cooling liquid produced by flash-distillation can enter the washing section through the liquid seal means while the flash-distilling section is in gas-phase isolation from the washing section, wherein a pressure in the flash-distilling section is lower than that in the washing section.

What is claimed is: 
     
       1. An exhaust gas separating tower, comprising:
 a washing section configured for washing an exhaust gas entering the tower with a cooling liquid so as to at least partially remove solid dust entrained in the exhaust gas, cool the exhaust gas, and condense at least a portion of moisture in the exhaust gas into liquid, the washing section comprising an exhaust gas inlet, an exhaust gas outlet arranged above the exhaust gas inlet, and a cooling liquid outlet for discharging the cooling liquid having washed the exhaust gas; 
 a flash-distilling section arranged above the washing section and configured for flash-distilling the cooling liquid from the washing section to produce a cooled cooling liquid to be provided to the washing section and a cooling liquid vapor, the flash-distilling section comprising a cooling liquid inlet through which the cooling liquid from the washing section enters the flash-distilling section, a flash-distilling space for performing flash-distillation therein, and a vapor outlet through which the cooling liquid vapor is discharged; and 
 a liquid seal means arranged between the flash-distilling section and the washing section, so that the cooled cooling liquid produced by flash-distillation is able to enter the washing section through the liquid seal means while the flash-distilling section is in gas-phase isolation from the washing section, wherein a pressure in the flash-distilling section is lower than that in the washing section. 
 
     
     
       2. The exhaust gas separating tower of  claim 1 , wherein the liquid seal means comprises:
 an upper partition plate arranged at a bottom of the flash-distilling section; 
 a lower partition plate arranged at a top of the washing section and separated from the upper partition plate; 
 at least one first downspout extending downwards from the upper partition plate, wherein each first downspout has a top opening arranged in the upper partition plate to communicate with the flash-distilling section, and a bottom opening close to the lower partition plate; 
 at least one second downspout extending through the lower partition plate, wherein each second downspout has a top opening arranged at a position higher than the bottom opening of the first downspout, and a bottom opening communicating with the washing section. 
 
     
     
       3. The exhaust gas separating tower of  claim 2 , wherein the liquid seal means further comprises a control valve for controlling a flow rate of the cooling liquid from the flash-distilling section to the washing section. 
     
     
       4. The exhaust gas separating tower of  claim 2 , wherein the liquid seal means comprises a plurality of the second downspouts, wherein distances between the top openings of the respective second downspouts and the lower partition plate are different. 
     
     
       5. The exhaust gas separating tower of  claim 4 , wherein the first downspout is arranged at about a center of a cross-section of the tower, while the plurality of the second downspouts are respectively arranged against a sidewall of the tower. 
     
     
       6. The exhaust gas separating tower of  claim 1 , wherein the washing section further comprises:
 a filler segment arranged between the exhaust gas inlet and exhaust gas outlet in a vertical direction, in which the cooling liquid from the flash-distilling section and the exhaust gas input via the exhaust gas inlet contact with each other in a counter-flowing manner; and 
 a liquid storage segment arranged at a bottom of the tower for storing the cooling liquid falling from the filler segment, 
 wherein the cooling liquid outlet is arranged at a bottom wall of the tower, via which the cooling liquid in the liquid storage segment is dischargeable. 
 
     
     
       7. The exhaust gas separating tower of  claim 6 , wherein the filler segment comprises at least one filling unit having one or more layers of fillers and at least one liquid dispenser, wherein above each filling unit there is one liquid dispenser. 
     
     
       8. The exhaust gas separating tower of  claim 7 , wherein each layer of the filler is selected from a bulk filler, a regular filler, a general sieve plate, an oriented sieve plate, and/or a multiple-downspout sieve plate. 
     
     
       9. The exhaust gas separating tower of  claim 6 , wherein the washing section further comprises a non-condensable gas removing segment arranged between the filler segment and the liquid storage segment, the non-condensable gas removing segment comprising:
 a filler layer, and 
 a vapor inlet pipe extending from the sidewall of the tower to the filler layer, via which a vapor can enter the filler layer so as to heat the cooling liquid passing through the filler layer, allowing the non-condensable gas in the cooling liquid volatilize therefrom. 
 
     
     
       10. The exhaust gas separating tower of  claim 6 , wherein the washing section further comprises an exhaust gas dispenser arranged below the filler segment, through which the exhaust gas input through the exhaust gas inlet is able to be evenly provided to the filler segment. 
     
     
       11. The exhaust gas separating tower of  claim 10 , wherein the washing section further comprises a spraying segment arranged between the filler segment and the exhaust gas dispenser, for pre-cooling and pre-washing the exhaust gas before the exhaust gas reaches the filler segment. 
     
     
       12. The exhaust gas separating tower of  claim 6 , wherein the washing section further comprises a gas demister arranged between the filler segment and the exhaust gas outlet, for removing mist droplets from the exhaust gas before said exhaust gas being discharged via the exhaust gas outlet, wherein a opening of the liquid seal means to the washing section is arranged at a height between the filler segment and the gas demister. 
     
     
       13. The exhaust gas separating tower of  claim 6 , wherein the washing section comprises a quantitative discharging port branching from the cooling liquid outlet, through which the cooling liquid in the liquid storage segment is quantitatively discharged to maintain solid dust content in the separating tower within a predetermined range. 
     
     
       14. The exhaust gas separating tower of  claim 1 , wherein the cooling liquid inlet of the flash-distilling section is arranged in the sidewall of the tower and above the flash-distilling space;
 wherein the flash-distilling section further comprises a cooling liquid dispenser arranged between the cooling liquid inlet and the flash-distilling space, for evenly distributing the cooling liquid input from the cooling liquid inlet into the below flash-distilling space. 
 
     
     
       15. The exhaust gas separating tower of  claim 14 , wherein the vapor outlet of the flash-distilling section is arranged at the top of the tower, the flash-distilling section further comprising a demister for removing mist droplets in the cooling liquid vapor produced by flash-distillation before the cooling liquid vapor being discharged from the flash-distilling section, wherein the demister is arranged below the vapor outlet and above the cooling liquid inlet. 
     
     
       16. The exhaust gas separating tower of  claim 1 , wherein the pressure in the washing section is at an atmospheric pressure, while the pressure in the flash-distilling section is about 2.5 kPa(A) to about 32 kPa(A). 
     
     
       17. An exhaust gas separating and recycling system, comprising:
 an exhaust gas separating tower, which comprises:
 a washing section configured for washing an exhaust gas entering the tower with a cooling liquid so as to at least partially remove solid dust entrained in the exhaust gas, cool the exhaust gas, and condense at least a portion of moisture in the exhaust gas into liquid, the washing section comprising an exhaust gas inlet, an exhaust gas outlet above the exhaust gas inlet, and a cooling liquid outlet for discharging the cooling liquid having washed the exhaust gas; 
 a flash-distilling section arranged above the washing section and configured for flash-distilling the cooling liquid from the washing section to produce a cooled cooling liquid to be provided to the washing section and a cooling liquid vapor, the flash-distilling section comprising a cooling liquid inlet through which the cooling liquid from the washing section enters the flash-distilling section, a flash-distilling space for performing flash distillation therein, and a vapor outlet through which the cooling liquid vapor is discharged; and 
 a liquid seal means arranged between the flash-distilling section and the washing section, so that the cooling liquid produced by flash-distillation is able to enter the washing section through the liquid seal means while the flash-distilling section is in gas-phase isolation from the washing section, wherein a pressure in the flash-distilling section is lower than that in the washing section; and 
 
 a pump connected between the cooling liquid outlet of the washing section and the cooling liquid inlet of the flash-distilling section, for delivering the cooling liquid that has washed the exhaust gas from the washing section into the flash-distilling section for flash-distillation. 
 
     
     
       18. The system of  claim 17 , wherein the liquid seal means comprises:
 an upper partition plate arranged at the bottom of the flash-distilling section; 
 a lower partition plate arranged at the top of the washing section and separated from the upper partition plate; 
 at least one first downspout extending downwards from the upper partition plate, wherein each first downspout has a top opening arranged in the upper partition plate to communicate with the flash-distilling section, and a bottom opening close to the lower partition plate; 
 at least one second downspout extending through the lower partition plate, wherein each second downspout has a top opening arranged at a position higher than the bottom opening of the first downspout, and has a bottom opening communicating with the washing section. 
 
     
     
       19. The system of  claim 17 , further comprising:
 a condenser, connected to the vapor outlet of the flash-distilling section, for receiving the cooling liquid vapor from the flash-distilling section, and condensing said vapor into liquid; and 
 a storage tank, for storing the condensed liquid from the condenser. 
 
     
     
       20. The system of  claim 17 , further comprising:
 an exhaust pump connected to the top of the storage tank, for discharging the non-condensable gas within the storage tank; and 
 a recycled water pump connected to a lower part of the storage tank, for pumping out the condensed liquid in the storage tank.